So there isn't all that much known about her, but what information there is out there on her, I found, and cited here. Here is the backstory:

"In the beginning there was only Chaos. Then out of the void appeared Erebus, the unknowable place where death dwells, and Night. All else was empty, silent, endless, dark. Then, Love was born bringing along the beginning of order. From Love emerged Light, followed by Gaea, the earth."

The Man in the Moon was the only man Phoebe could really look up to, and place she could go to, into his arms. So, she left that whole terribly dysfunctional family situation, and went straight to the moon, for she had had enough. Who knows how cruel Uranus was to her, or for how long he was, but her fellow Titans, eventually murdered him he was so bad. She did not participate in that, for she had already gone off, having turned her back on it all, and spent time hanging out far away from it all, reading books, and doing what she wanted, enjoying the cosmos in peaceful quietude.

So, she had a messed up childhood and teenage years. But it did not end tragically for her in her adult years.

This scene is just before she entered into a relationship with Coeus, whom she married, and with whom she had two daughters to, named Asteria and Leto. He was a real man she could actually look up to, unlike Uranus, or the Man in the Moon, for he was really just "an imaginary person whose face some people think they see on the surface of the moon" (source: www.macmillandictionary.com/us… )

I imagine Coeus coming to her there, telling her that Uranus' tyranny is over, and that it's finally okay for her to come back to the family again. Coeus is said to have a great mind, possess much intelligence, and such brilliance attracted her, so she fell MADLY in love with him instantly. And as we know, she's enchanting, so he fell MADLY in love with her. So that's how I imagine their relationship began. They make such a cute coupling, so like-minded, like-hearted, like-kinded they are, such kindred spirits, but not much more is known about the two of them, other than them marrying and having two daughters together. Those two daughters of theirs, had children of their own, three total, named Apollo, Artemis, and Hectate.